1. Field of the Invention
This invention relates to a crosslinkable polysilane composition which cures into a solvent--insoluble, tough, crosslinked polysilane film, and a cured product thereof.
2. Prior Art
Among siloxane compositions, those compositions which cure through hydrosilylation reaction have the advantage that curing takes place quickly to the deep interior without forming by--products and thus have found a wide variety of applications, for example, as molded rubber, adhesives, potting compounds for electric and electronic parts, release coatings for paper and film, and the like.
One reported examples of curable polysilane compositions which cure through hydrosilylation reaction is Robert West, Journal of Organometallic Chemistry, Vol. 300, pp. 327-346, 1986, which describes a composition comprising a polysilane having hydrogen as a side chain substituent and trivinylphenylsilane, which is cured with a chloroplatinic acid catalyst. This system, however, has the problem that the side chain substituent is less reactive so that the polysilane chain may be scissored by the chloroplatinic acid catalyst and then oxidized.
Also reported in the same literature are a polysilane curing method using a photo--crosslinking reaction of a polysilane having an alkenyl group in a side chain alone and a curing method using a photo--crosslinking reaction between a polysilane and a polyfunctional unsaturated compound. These methods rely on scission of the polysilane chain and thus have the problem that the crosslinked film cannot retain the properties of polysilane.
Most polysilanes are soluble in various conventional organic solvents and films can be formed from such polysilane solution. However, it is difficult to form thick films by increasing the solution viscosity because a certain limit exists in solubility. Thus the use of polysilanes is limited in applications requiring thick films.